It looks like we should see our peak color pretty much on schedule this year. The best color over the northern mountains should be from September 20th to the 30th. The central mountains will be about five days behind, with the southern mountain areas rounding out the last days of the month and the first ten days of October.Perhaps the most appealing part of autumn is the gold found in the mountains each year. Not the gold sought by prospectors over a century ago, but rather the gilded glory of Colorado's famous aspen trees. The decrease in sunlight switches off the mechanism in the leaves that creates chlorophyll - the green color in the leaf. As the green fades, the gold color dominates until dying leaf flutters to the ground. The best years for aspen viewing are those with well-timed rains and no major fall storms. A too dry summer will send the leaves falling quickly, while a wet summer tends to make them darken to brown or black. The most brilliant display of aspen occurs when we have a mild late summer and periodic gentle rain, combined with a dry September that includes few big windstorms or early snows.Usually the first signs of aspen gold begin in mid to late August over the higher forests of central and northern Colorado. By the second and third week of September, many aspen groves are well worth a day's drive. Usually the peak time to view aspen is around the last weekend of September. After that, early snows will knock down the leaves and others drop away by themselves. Aspen color does not vary nearly as much as the rich reds and purple leaves of the Midwest and East, but there is something about gold leaves against a backdrop of rich evergreen and deep blue sky that makes our fall mountains special indeed!Nothing says "autumn" in Colorado quite like the sight of a mountainside covered in the stunning leafy gold of aspen trees. Colorado's famous high country aspen reliably turn gold from the second week of September through the first week of October. Populus tremuloides - or the quaking aspen - can be found in all eleven of Colorado's national forests and their autumn fireworks are worth the drive.Aspen naturally propagate in areas where hardier trees have been damaged or destroyed. This was the case in Colorado, where the slender trees grew in after logging stripped trees from mountain areas. Characterized by their elaborate root systems, aspen reproduce by sending up suckers from the roots to create "clone" stands of trees. These clones, connected underground at the root, are genetically identical to the mother tree. The identical nature of a clone stand is most obvious in springs, when each tree in the stand leafs at the same time, and in fall, when each tree turns the same shade of gold.Historically, native tribes used the aspen bark to make medicinal teas to alleviate fever. The inner bark was sometimes eaten raw in the spring, and the outer bark occasionally produces a powder that was used as a sunscreen. Aspen is a favorite of Colorado wildlife too. Beaver use aspen for food and building; elk, moose, and deer eat the twigs and foliage. Other names for quaking aspen are golden aspen, mountain aspen, popple, poplar and trembling poplar.Despite Coloradans' affinity for aspen, these delicate trees are not highly recommended for residential landscaping, especially at lower elevations of the state. Aspen as susceptible to many diseases, their convoluted root systems often grow into sewage drainage systems, and they generally last no longer than about 10 years out of their native habitat. And for a listing of the the great places to view the aspen gold, check out my list of favorite drives to see fall colors. Information about our aspen leaves will help you plan your trip. It truly is a wonderful way to spend a day -- when the aspens are in their full glory!